Submarine signaling.



No. 852,647. PATENTED MAY 7, 1907Y L. I. BL

SUBMARINE NALING.

APPLICATION FILED. JARS. 1907.

2 SHEETS-SHEET 1.

4 A l I PATBNTED MAY '7, 1907.

L. I. BLAKE. SUBMARINE SIGNALING. APPLICATION FILED IAN.a.19ov.

3 V ....,ILM

UNITED sTATEs PATENT oEEIoE.

LUCIEN I. BLAKE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO SUBMA- RINE SIGNAL COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORA- TION OF MAINE.

SUBNIARINE Specification of Letters Patent.

SIGN/mue..

Patented May 7, 1907.

Application filed January Q, 1907. Serial NoI 351,361.

A citizen of the United States, residing at Besis fa specification, reference being had to the invention upon which -my present applicatin 1s based, involves a knowledge of the ary Walls is called a resonance cavity.

l the principle hereinafter descri becomes a reinforcer of sound, Whether reempliiied inthe case reilected left in the latter through or at which vibraton, in the county of Suffolk and State of Massachusetts, have invented or discovered certain' new 'and useful Improvements in Submarine Signaling, of which the following l I i i l l drawings accompanying and forming part of the same.

As an understanding of the nature of the phenomenon of resonance, the following statement of Well recognized principles is apposite. .The fundamental principle of acoustic resonance is reflection. .In any portion ofV a aseous medium Which is isolated,-by Wich term as used herein is meant Wholly or partially confined by. boundary Walls of any suitable material differing in its physical roprties from the inclosed medium,-a re ection occurs at the surface of the boundary wall/s, of any acoustic dis-- turbance resent in that medium. This isturbance Will travel back and forth between the Walls or boundaries to produce a tone of definite pitch, dependent upon the volume and shape of the medium inclosed. The chamber or cavity formed by the bou'ilde method of exciting a given m'edium to resonance is immaterial. It may be effected bysound. vibrations brought into it from an outside and remote source, or by vibrations originating Within, the fcavity itself. It is not necessary in any of the applications of ed, or in general, that the cavity be entirely surrounded byreflecting Walls, for an opening may be tions may be imparted to the medium within the cavity, and another through which the re lar periodic vibrations of the medium a ectedv ma' be communicated to any other medium Wit out the boundaries of the cavity. TheJ function ofthe resonance cavity thus ceived or produced.

In all aerial sound producers resonance chambers are the essential elements for giving intensity of sound. Their action is exo'f organ pipes and whis- 1 ties. In these the column of airY inclosed Within the Walls of the resonance chamber is set into-regular periodic or harmonic vibration at the embouchure by either the so-calledfiute mouth-piece or a reed. When the length of the air column is great in comparison with its other dimensions, as in the case 'of a pipe, the pitch is controlled by the period of travel of the disturbance from end to end of the pipe, and this is called the free period of the pipe. In the ute mouthpiece form a thin Jet of air or steam impinges upon the sharp edge of an opening into the chamber and the rhythmic elfect of friction produces a vibrating reed of air or steam which is continually lcontrolled in its rate of vibration by the regular periodic vibrations of the column of air in the pipe.

In the' case of the reed mouth-pi-ecc the reed is set in vibration by' the air or steam impinging upon its unconfined edge, and the air or .steam column sustains and reinforces these vibrations, controlling their rate and consequently the pitch of the tone if the reed be not too stiff. In either case the free vibration of the column within the pipe or chamber is the essential source of sound.

In connection with the consideration 'of the 'action or effect of these resonance cavities, it is important to bear in mind the distinction between the free vibration of the in"- c'losed medium and the forced vibrations -Which occur inA consonant materials excited by any source of sound. In the phenomenon of resonance, one definite pitch is conspicnous or natural for each given set ,of conditions, While in the case of consonance, sounds of any pitch are reinforced. In the lformer the size and shape of the mass of confined medium control in determining the pitch, the

. character-of the'containing Walls, within certain limits hereinafter more fully explained, being immaterial provided they are capable of reflecting the disturbances; While'in the latter, the physical character of the consonant body'is the controlling consideration, size and shape being immaterial. Y

I have discovered and practica-ll y demonstrated that under proper conditions aliquid medium may be readily brou ht into sonorl ous resonance with a tone of given pitch, anc

that an isolated portion of liquid mediun possesses, according to its dimensions, acerwithin a body of liquid the latter may be caused to strongly reinforce these vibrations .and consequently intensify the sound produced by them. Such a liquid mass will also reinforce'sounds delvered'into it from a ,distance, whereby Weak tones will he rendered more audible, so that'it may, therefore, be utilized, like an aerial resonator, both for vthe production and reception of sounds. Availingmyself of this discovery, I have employed l liquid resonators in systems of submarine signaling with results of a highly useful and novel character. A

The desirability of securing the advantages of resonance for intensifyilng sound, either produced fortransmission or received from a distant source, in the artoi submarine signaling, has been recognized by those skilled in the art. in fact, self sults in the As an abstract proposition it is, suggestive from analogous reapplication of the same broad principle in the case of wind instruments, whistles, and in general those devices in which a sound of given pitch is reinforced by a reso,- nating body of air or gas. No useful or practical application' of the, principle tonsubma# rine signaling, however, has ever been made, so far as I am aware, and for thereason, which my discovery has now rendered apparent, thatconditions essential to the attainment of theresonance of isolated'bodies of liquid, have not been recognized or secured in any apparatus 'that has been designed or proposed for use either .as producers or receivers of sound Under Water. l n

In all wind instruments and other devices\ in which the resonance of a coniined or isolated body of air isutilized', the resonating. medium is of such a highly compressible nature in comparison with the materials ordi-'- nal'ily constituting its boundaries, that the j latter may be of almost any rigid material, such as wood, paper or very thin metal. If, however, the medium which it is desired to set into resonance be a liquid, which is vpractically incompressible as compared with `any gas, the rhythmic changes of ressure WithinA it which correspond to soun, exert exceedingly powerul'total pressers over the`boundary walls of the chamber or cavity contain-v ing the liquid, according to the laws` of hydrostatics'. Such pressures, asis well known, may bend and even .burst Walls of ordinary strength. Therefore, if liquid 'resonators be constructed 'without due regard to theeffect upon the-retaining walls of these variations of hydrostatic pressure, they present :onditions.which actually remove the elements upon `which refiection depends, but the effect of' which is .negligible when the nedium is an easily compressible gas, such is ain'. It is forv this reason that a Water produce resonance, This may be conclusive y demonstrated by the following experiments: If a pipe 4 inches in cross sectional. area and several feet long be made oi hard metal, say1/8 of an inch thick, which i wouldl produce very much greater vrigidity than would be required in any ordinary toneproducing instrument, and provided with an embouchure similar to that of an organ pipe, it may, if submerged Ain water,I be operated to produce 'a tone by a jet of Water in theby air. It will befound, however,that the tone produced has a pitch wholly independe ent nance. The reason for this, as I have found, is that the rigidityy of the walls is not suffe' cient to withstand' the variations' in hydrostatic pressure and thereby reflect the regular periodic orharmonic vibrations imparted l(to the mass of liquid within the pipe. If the walls of the pipe yield, then any change in the pressure originating at the. embouchureof the inclosed liquid will be instsintly relieved atthat point, and therefore no change in pressure will be ropagatedthrough the pipe to undergo re ection, and thereby to produce resonance, .In short, the liquid column remains quiescent at `its normal pressure, and'takes no part whatever in the production or reinforcement of the length Vof the pipe, thus showing that the water column isv not set in reso.

same manner as an organ pipe 'is operated.

of sound. If the same pipe, however, be made of veryihard` and toughsteel, with walls even more unyielding than the practically incompressible 'water surrounding them, it will be found to produce, whenoperated by a water jet in thesame Way, a tone of definite pitch that varies with the length of vthe pipe, thus proving that the liquidmass within `the- 'saine is brought into resonance'. Tofconveyv ani-idea of what is required in securingthe quid resonator, it maybe stated that air is over twenty thousand'times more com-` pressible than water; andwaterover sixty' times more compressible than hard steel, so.

loo

proper character of ',inclo'sing walls `for a @that to secure the requisite rigidity of' the walls in the case of a'liquid resonator I have foundl it necessary to build'v them v,up

shrinking very tough steel, tubesluponone anlqthe1r..-. h ym t e princi thatpihe bundary wal cavity for a liquid resonator must be of this .special character in order to 'withstand,the variations efl' hydrostatic pressure, y' aind- *therebyi produce the. reflection character@A -is tic,.of` resonance, I have produced appale i of the 4`discovery ratus Vfor use in systemsof submarine sig; A1.25. l

ynaling capable of intensifyingsounds,bot sent and received,- and which'possesses all, the advantages in submarine-work which: ldistinguish similar devices foraerial spande.

olumn in an ordinary organvpipe does not producing and signaling purposes, and

s of the chamber or i of steel.

have always been recognized and adoptedy description and specific claims relate mainly` to the latter, vas my improvements in sound receivers constructed in accordance with this principle, are illustrated and claimed more in detail in'other applications.

i Referring now to Ythe accompanying drawings: Figure 1 is a vieW in elevation of a sound producer embodying `my invention, showing the means for operating the same. Fig. 2 is a longitudinal cross section of the operative parts of the sound producer. Fig. 3 is a sectional vieW- of a sound receiver.

Referring to Figs. 1 and 2, A is a cylinder It is shown as closed-at one. end with the other open and beveled on an angle of about 60 degrees to sharp edges., It is not necessary that the cylinder be closed, but, as will be understood, to secure the same free eriod of vibration of-a column of liquid Wit in it, an open cylinder ,must be of double the length. In practice I have found that for good results a cylinder designed for a iven pitch and havin a bore of 3 inches in c iameter and 11 inc es' long should have Walls 1-1/2 inches in thickness of very hard and tough steel built up by shrinking several tubes, one over the other. B, B, are side'bars connecting the heads C, D, of a r` id frame. In

the head C is secured, or integra with it is cast',

a chamber E, provided with an inlet through which water is introduced by a pipe G from any suitable source capable of delivering it at a `high pressure. Within the chamber E is a spider H carrying a plate K of slightly smaller diameter than an opening in the end of the chamber, and which therefore leaves anannular orifice L preferably of about 1 32 of an inch in Width. In the head D is a circular opening with threaded Walls with which corres onding threadson the exterior of the cylin er A engage. By this means the cylinder rigidly supported with its beveled edge in proper position relative to the annular orifice L and with the capability of adjustment with respect thereto. The cylinder A is adjusted to bring its edge in close proximity tothe annular orifice L, andf is submerged at any desired point Where the sounds or`signals are to be produced. Water und er pressure, preferably from 125 to 200 pounds, isthen supplied to the chamber E, and issu' therefrom .in the form of an annular jet impmges upon the edges and beveled end of the cylinder A, with the result that harmonic or regular periodic l'vibrations are set up in the column of Water WithinV the cylinder.

These vibrations, Aowing. to the unyieldmg character yof the boundarles of the chamber or cavity in which may be adjusted to wary the column of Water is contained are reflected backand forth from the Walls and the column is therefore set in sonorous resonance. Such an apparatus will produce a tone of definite pitch dependentV upon the dimensions of the chamber or cavity within the cylinder A. I

have found that sounds thus produced will be carried to great distances through Water and may be detected and rendered audible by suitable sound receiving instruments the more readily because of their distinctive musical character. By interrupting or varying Ythe pressure of the water suppliedn to the chamber E, or by deiectiug the jet issuing from the orilice in said chamber, distinctive signals, according to any prearranged code.

may be sent bythis device.

In Fig. 3 I have shown the application ol my discovery to'a device for receivin sound.

S represents a portion of the skin o. a steel vessel, Which V1s selected for purposes ofillustration. To the inner surface of the skin is secured, as by means of bolts P passing through ianges at its end, a steel cylinder M of the same character'as that described in connection With Figs. 1 and 2. vThe opposite or inner'end of the cylinder M is closed by .a head N of corresponding thickness, the edges of which are threaded to engage With threads in the inner surface of the cylinder. A small orifice V is formed in the head N and an ordinary microphonic transmitter T is secured over the same 4so as to be operated by the resonance of the column of water 'containedl in the cylinder M. Wires O, O connect the microphone with` an ordinary telephoneI receiver. A small opening R may -be drilled through the ships skin 1n order to permit access of the Water into the cylinder M, but this isnot necessary for reasons previously described, as sounds coming throu h the Water would be transmitted through t e wall of the ship -to the Water column 1n the cylinder M, even Were no passage of commui mcation present. The head N, by means of its threaded connection with the cylinder M,

the chamber Within the cylinder, and thus control the pitch of the resonant cavity in order to tune it to any desired source of sound. In this device the column of water Within the cylinder M will be'set in resonant vibration the dimensions ofr l by a given sound transmitted to it throu h 4the Water and entering either through t e ships Wall or the .opening R. The sound thus intensified ov erates the microphone, which produces in t e telephone receiver an audible sound. f l a While I have described the inventlon by reference to specific forms of apparatus, it

is evident that their construction may be greatly varied. In general, the sound producer may be submergd at any selected station orplaced in a tan attached to the Walls of a vessel. The receive'r may be similarly located so that by means of the ap aratus signals may be transmitted from the s ore to avessel, or conversely, or between vessels -within the limits of practical transmission.

What I now claim as my invention is 1. The improvement in the art of submarine signaling by soundfwhich consists in intensifying the sounds produced or received the resonance of an isola'ted mass 'of liquid, as set forth.

k2. The improvement/ in the art of submarinesignaling by sound, which consists in n,producing regular pei'iodic or harmonic vi- .l within the same, and reflecting the said viuid contained within the same, and reflecting brations in an isolated body of liquid, and` producing by the resonance of such body intensified sounds, as set forth.

3. A liquid resona'tor consisting of a receptacle with walls capable of withstanding the variations of hydrostatic pressurel accompanying regular periodic or harmonic vibra itions set up in a body of liquid contained brations to produce resonance, as set forth.

f4. A liquid resonator comprising in combination a receptacle with'walls capable of withstanding the variations of hydrostatic pressure accompanying regular periodic or iarm'mic vibrations set up in a body of liqthe said vibrations to produce resonance, and means for setting up such vibrations in the liquid, Aas set forth. i

5. A sound-producer for submarine signaling, comprising a receptacle withv Walls capable oflwithstanding the variations of hydrostatic pressureaccompanying regulai periodicsvibrations in a body of liquid contained therein, and'reflecting they same to produce resonance, and means for imparting such vibrations tothe liquid, as set forth.

eeen-i7.

' 8. A submarine sound producerhcompris-Y orifice with sharp edges -f'an'd constituting a jet of liquid to impinge-upon the edges for producing a rhythmic vibration vof the liquid contained in the rece tacle, as -set forth. v

9. In a sound pro ucer for submarine signaling, the `combination with a sourceof rhythmic vibrations, of a resonating cavity capable ofwithstanding the variations in hydrostatic pressure' accompanying the vvi- J.brations imparted to the liquid contained ing, in combination, a receptacle having an composed of a hollow cylinder with wallsf resonating cavity, and means for. causing a thereinandrellecting the same to-produce resonance,'as set fort 10. In a sound producerv for submarine signaling, a liquid resonator 'composedof a cylinder of hardened-steelwalls of a thickness capable of withstanding'- the variations in hydrostatic pressure accompanying the harmonicv vibrations of 'a column of Water contained within the cylinder, as set forth.

LUCIEN -IL Witnesses: 4

FULTONv BLAKE.,

J. CONVERSE GRAY. 

